Composite articles made by joining brass part and silicon carbide ceramic part

ABSTRACT

A process for joining a brass part and a silicon carbide ceramic part comprising: providing a brass part, a SiC ceramic part, a Al foil and a Ni foil; placing the SiC ceramic part, the Al foil, the Ni foil, and the brass part into a mold, the Al foil and the Ni foil located between the SiC ceramic part and the brass part, the Al foil abutting against the SiC ceramic part, the Ni foil abutting against the brass part and the Al foil; placing the mold into a chamber of an hot press sintering device, heating the chamber and pressing the brass part, the SiC ceramic part, the Al foil, and the Ni foil at least until the brass part, the SiC ceramic part, the Al foil and the Ni foil form a integral composite article.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosures of the three listed applications are incorporated byreference in this instant application. All listed applications have thesame assignee.

Attorney Current Ser. No. Docket No. Title Inventors Status 13/172,264US36181 PROCESS FOR JOINING HSIN-PEI Pending STAINLESS STEEL PART CHANGAND ZIRCONIA et al. CERAMIC PART AND COMPOSITE ARTICLES MADE BY SAME13/172,271 US36184 PROCESS FOR JOINING HSIN-PEI Pending BRASS PART ANDCHANG SILICON CARBIDE et al. CERAMIC PART AND COMPOSITE ARTICLES MADE BYSAME 13/172,274 US36185 PROCESS FOR JOINING HSIN-PEI Pending BRONZE PARTAND CHANG SILICON CARBIDE et al. CERAMIC PART AND COMPOSITE ARTICLESMADE BY SAME

BACKGROUND

1. Technical Field

The present disclosure relates to a process for joining a metal part anda ceramic part, especially to a process for joining a brass part and asilicon carbide ceramic part, and a composite article made by theprocess.

2. Description of the Related Art

Brass has excellent corrosion resistance and good conductivity comparedto steel, and is widely applied in the components manufacturingindustry. However, unlike silicon carbide, brass cannot maintain itsphysical properties when used in an environment of high temperature andstrong corrosives. Therefore, a composite article comprising a brasspart and a silicon carbide ceramic part has a desirable performance ofhigh temperature resistance, corrosion resistance, abrasion resistance,and usable in extreme environments.

A typical process for joining brass and silicon carbide ceramic is bypositioning one or more separately formed intermediate connecting layersbetween brass and silicon carbide ceramic. However, due to differingrates of heat expansion and the separate nature of the intermediateconnecting layers, the bond between the brass and the silicon carbideceramic is not as stable as desired.

Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the exemplary process for joiningbrass part and silicon carbide ceramic part, and composite article madeby the process. Moreover, in the drawings like reference numeralsdesignate corresponding parts throughout the several views. Whereverpossible, the same reference numbers are used throughout the drawings torefer to the same or like elements of an embodiment.

FIG. 1 is a schematic cross-sectional view of an example of a hot presssintering device for implementing the present process.

FIG. 2 is a cross-sectional view of an exemplary embodiment of thepresent article made by the present process.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary process for joining a brass part and asilicon carbide ceramic part, may includes the following steps:

A silicon carbide (SiC) ceramic part 20, a aluminum (Al) foil 40, annickel (Ni) foil 50 and a brass part 30 are provided. The Al foil 40 andthe Ni foil 50 are used as a joining medium between the SiC ceramic part20 and the brass part 30. Each of the Al foil 40 and the Ni foil 50 hasa thickness in a range from about 0.1 millimeter (mm) to about 0.5 mm.

The SiC ceramic part 20, the brass part 30, the Al foil 40 and the Nifoil 50 are pretreated. The pretreatment may include the step ofpolishing the surfaces of The SiC ceramic part 20, the brass part 30,the Al foil 40 and the Ni foil 50 by silicon carbide (SiC) sandpaper toproduce smooth surfaces. Then, the SiC ceramic part 20, the brass part30, the Al foil 40 and the Ni foil 50 are cleaned by placing them intoan organic solution to remove grease from their surfaces. The organicsolution can be ethanol, and/or other organic solvents. Then, the SiCceramic part 20, the brass part 30, the Al foil 40 and the Ni foil 50are rinsed with water and dried.

A clamping mold 70 is used to hold the SiC ceramic part 20, the brasspart 30, the Al foil 40 and the Ni foil 50. The clamping mold 70includes a pressing board 72, a corresponding supporting board 74 and areceiving board 76. The receiving board 76 defines a cavity 762 runningthrough the upper/bottom surface to receive the SiC ceramic part 20, thebrass part 30, the Al foil 40 and the Ni foil 50. The pressing board 72and the corresponding supporting board 74 extend towards the cavity 762from opposing directions and can be moved relative to the cavity 762 bya driving system such as hydraulic pressure system. The SiC ceramic part20, the Al foil 40, the Ni foil 50 and the brass part 30 are placed intothe cavity 762 and clamped by the pressing board 72 and thecorresponding supporting board 74. The Al foil 40 and the Ni foil 50 areinserted between the SiC ceramic part 20 and the brass part 30. The Alfoil 40 abuts against the SiC ceramic part 20, the Ni foil 50 abutsagainst the brass part 30. The pressing board 72 and the correspondingsupporting board 74 from two opposite sides, brings the surfaces of theparts to be joined into tight contact, for compressing the SiC ceramicpart 20, the Al foil 40, the Ni foil 50 and the brass part 30.

A hot press sintering device 100 including a chamber 101 is provided.The clamping mold 70 is placed into the chamber 101. The vacuum levelinside the chamber 101 is set to about 10⁻³ Pa to about 9×10⁻³ Pa. Argon(Ar) is fed into the chamber 101 to maintain the chamber 101 pressure ina range of about 0.3 MPa-0.6 MPa. The pressing board 72 and thecorresponding supporting board 74 press toward each other at about 10MPa to firmly clamp the SiC ceramic part 20 and the brass part 30. Then,the chamber 101 is heated at a rate of about 10 degrees Celsius perminute(° C./min)-20° C./min. When the temperature of the chamber 101reaches to about 300° C., the clamping pressure applied by the boards72,74 steadily increases, until the temperature of the chamber 101reaches to about 700° C.-1000° C., and the clamping pressure reaches toabout 10 MPa-50 MPa. The pressure and heat are maintained in theirrespective peak ranges for about 30 min-70 min, so that the Al foil 40and the Ni foil 50 will chemically interact with each other, and the Alfoil 40 chemically interacts with the SiC ceramic part 20, and the Nifoil 50 chemically interacts with the brass part 30. Accordingly, theSiC ceramic part 20 and the brass part 30 are connected by the Al foil40 and the Ni foil 50 to form a composite article 10. The compositearticle 10 is removed after the chamber 101 is cooled.

Referring to FIG. 2, in the process of making the composite article 10,the Al foil 40 and the Ni foil 50 act as intermediate layers to form aconnecting layer 80 that connect the SiC ceramic part 20 and the brasspart 30. The heat expansion rate of SiC ceramic part 20 is approximatelyequal to that of the Al foil 40, thus the SiC ceramic part 20 cansubstantially connect with the Al foil 40. The heat expansion rate ofthe brass part 30 is approximately equal to that of the Ni foil 50, thusthe brass part 30 can substantially connect to the Ni foil 50.Furthermore, the combination of the Al foil 40 and the Ni foil 50 toform the connecting layer 80 results in a connecting layer 80 having arate of heat expansion that gradually changes from one end to the other.Therefore, the SiC ceramic part 20 is securely connected with the brasspart 30 and more able to cope with temperature changes.

The composite article 10 manufactured by the present process includesthe SiC ceramic part 20, the brass part 30 and a multi-layeredconnecting layer 80 connecting the SiC ceramic part 20 to the brass part30. The connecting layer 80 is formed by placing the Al foil 40 and theNi foil 50 between the SiC ceramic part 20 and the brass part 30, andthen heating and pressing the SiC ceramic part 20 and the brass part 30as previously described. The various layers of the connecting layer 80result from differing chemical interaction between the brass part 30, Alfoil 40, Ni foil 50, and SiC ceramic part 20. In particular, theconnecting layer 80 includes:

a) a first transition layer 81: The first transition layer 81 mainlyincludes compounds comprising Al element and C element, and chemicalcompounds comprising Si element and Al element, such as Al₂C₃, etc. Thecompounds result from chemical reactions between adjacent portions ofthe SiC ceramic part 20 and Al foil 40;

b) a Al layer 82: The Al layer 82 results from portions of the Al foil40 that do not chemically react with either the SiC ceramic part 20 orthe Ni foil 50;

c) a second transition layer 83: The second transition layer 83 islocated between the Al layer 82 and the Ni layer 84. The secondtransition layer 83 mainly includes chemical compounds comprising Alelement and Ni element, and Ni with Al solid solutions. The compoundsand solutions result from chemical reactions between adjacent portionsto the Al foil 40 and Ni foil 50;

d) an Ni layer 84: The Ni layer 84 results from portions of the Ni foil50 that do not chemically react with either the Al foil 40 or the brasspart 30; and

e) a third transition layer 85: The third transition layer 85 is locatedbetween the Ni layer 84 and the brass layer 30 and connects the Ni layer84 and the brass layer 30. The third transition layer 85 mainly includeschemical compounds comprising Ni element and Cu element, and Ni with Cusolid solutions. The third transition layer 85 further includes somechemical compounds comprising Ni element and Zn element, and Ni with Znsolid solutions. The brass layer 30 generally includes zinc (Zn) elementand the ratio of the Zn element in the brass is about below 10%. Thecompounds and solutions result from chemical reactions between adjacentportions to the Ni layer 84 and the brass layer 30.

The thermal expansion rate of the connecting layer 80 gradually changesfrom a value close to that of the SiC ceramic part 20 (in the area ofthe first transition layer 81) to a value close to that of brass part 30(in the area of the third transition layer 85). This results in acomposite article 10 well suited to temperature changes due to thegradual, rather than abrupt, changes in its internal thermal expansionrates.

Furthermore, the connecting layer 80 of the composite article 10 has nocracks or apertures, and has a smooth surface. The composite article 10has high hardness, high temperature resistance, corrosion resistance,abrasion resistance, shear strength in a range from about 50 MPa toabout 80 MPa, and tension strength in a range from about 60 MPa to about100 MPa.

It is to be understood that even though numerous characteristics andadvantages of the present embodiments have been set forth in theforegoing description, together with details of assemblies and functionsof various embodiments, the disclosure is illustrative only, and changesmay be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the present invention tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

What is claimed is:
 1. A composite article, comprising: a SiC ceramicpart, a brass part, and a connecting layer connecting the SiC ceramicpart to the brass part, wherein the connecting layer is formed byplacing a Al foil and a Ni foil between the SiC ceramic part and thebrass part with the Al foil adjacent to the SiC part and the Ni foiladjacent to the brass part, then heating and pressing the SiC ceramicpart, the brass part, the Al foil and the Ni foil, the connecting layerorder including a first transition layer adjacent to the SiC part, a Allayer, a second transition layer, a Ni layer, and a third transitionlayer adjacent to the brass part, the first transition layer that islocated between the SiC ceramic part and the Al layer mainly includescompounds comprising Al element and C element.
 2. The composite articleas claimed in claim 1, wherein the compounds include Al₂C₃.
 3. Thecomposite article as claimed in claim 1, wherein the second transitionlocated between the Al layer and the Ni layer mainly includes compoundscomprised of Al element and Ni element, and Ni—Al solid solutions. 4.The composite article as claimed in claim 1, wherein the thirdtransition layer located between the Ni layer and the brass layer mainlyincludes Ni element and Cu element, and Ni—Cu solid solutions.
 5. Thecomposite article as claimed in claim 4, wherein the third transitionlayer further includes Ni element and Zn element, and Ni—Zn solidsolutions.